Aqueous liquid for primers

ABSTRACT

Aqueous liquid for primers are prepared from a copolymer consisting essentially of the following components (A), (B) and (C) in aqueous medium where (A) is a cationic monomer represented by the following general formula (1) ##STR1## wherein Y is organic or inorganic monovalent anion; m is an integer 0 to 3 and n is an integer 1 to 3; 
     (B) is an alkoxysilane monomer represented as the following general formula (2) ##STR2## (C) is an ethylenic unsaturated monomer, and wherein a structural unit derived from the (A) component accounts for not less than 5% of the copolymer, a structural unit derived from the (B) component accounts for not less than 0.5% by weight of the copolymer and a structural unit derived from the (C) component accounts for not more than 94.5% by weight of the copolymer.

FIELD OF THE INVENTION

The present invention relates to aqueous liquid for primers which isapplied to improve surface of alkaline porous inorganic base materialssuch as concrete, mortar and the like.

BACKGROUND OF THE INVENTION

Because their surface layers are fragile, primers are usually applied onthe surface of inorganic cement building materials such as concrete,mortar, slate and the like for the purpose of improving the surfacereinforcement or adhesive strength to paints for surface finish and thelike. Heretofore, solvent primer liquid formed by dissolving syntheticresin into organic solvent has been employed as such primers. However,the solvent primer liquid is easy to ignite because of its volatilityand further it affects the human body when the fumes are breathed. Thus,the above solvent primer liquid has many problems from the viewpoints ofsafety, sanitation, and the like.

The present application has previously developed aqueous liquid forprimers wherein water is medium and organic solvent is not employed asmedium, and has already applied to the Japanese Patent Office (JPA62-80694). And, also as a further developed version, he developed oneliquid type primer, which is formed by copolymerizing dimethylaminoalkylamide acrylate or epichlorohydrin adduct of dimethylaminoalkylamide methacrylate as a function group and alkoxysilaneelement to be the aqueous resin superior in reinforcement effects of thesurface layer of base materials by crosslinking irrespective of thealkaline degree of base materials and already filed an application.

Although the above aqueous liquid can form a coat superior in waterproofby crosslinking under both circumstances of acid and alkali, when theconcentration of resin is raised, shelf stability deteriorates due tohigh viscosity. In addition, it has a defect that the permeability toinorganic building material, reinforcing ability to base materials andwaterproof properties deteriorate due to a rise of viscosity.

OBJECT OF THE INVENTION

The object of the present invention is accordingly to provide aqueousliquid for primers superior in permeability and reinforcing ability tobase materials and waterproof properties by forming resin liquid in highconcentration and low viscosity without loss of crosslinking reaction.

SUMMARY OF THE INVENTION

In the first aspect, this invention relates to the aqueous liquid forprimers, which contains a copolymer mainly formed with the followingcomponent (A), (B) and (C) in aqueous medium, where (A) is a cationicmonomer represented as the following general formula (1) ##STR3##wherein Y is organic or inorganic monovalent anion; m is an integer 0 to3 and n is an integer 1 to 3.

(B) is an alkoxysilane monomer represented as the following generalformula (2) ##STR4##

(C) is an ethylenic unsaturated monomer; and wherein a structural unitderived from the (A) component accounts for not less than 5% (by weight;the same applies hereinafter) of the copolymer, a structural unitderived from the (B) component accounts for not less than 0.5% of thecopolymer and a structural unit derived from the (C) component accountsfor not more than 94.5% of the copolymer.

In addition, in the second aspect, the invention relates to the aqueousliquid for primers which contains dispersedly a polymer found bypolymerizing ethylenic unsaturated monomer in the above aqueous liquid.

That is, the invention has performed a series of studies focused onwater soluble resin, especially acrylic resin, to find an aqueous liquidfor primers, which forms a strong coat having durability irrespective oftypes of base materials (inorganic building materials) and furthermoreis superior in waterproof properties by forming high-concentrated andlow viscous resin liquid. He found out that, as a result, when specialmonomers (component A and component B) represented as the above generalformula (1) and (2), and an ethylenic unsaturated monomer (component C)are polymerized at a specific ratio, a chain polymer obtained shows agood solubility in water and furthermore the aqueous solution penetratesthe surface layer of base material very well so as to reinforce thebasic material surface strongly, and at the same time to form a coatsuperior in waterproof and alkali resistance. Furthermore, he found outthat high concentrated and low viscous resin liquid was realized bypolymerization with cationic monomer represented as the above generalformula (1), without deteriorating the speed of crosslinking reactioncompared with prior methods, so that even in a coating condition of highconcentration, permeability to inorganic building materials remainsfavorable, and adequate reinforcement toward basic materials andwaterproof were given.

In addition, it was found out that similar effect was obtained inpolymerizing the above ethylenic unsaturated monomer solely by emulsionpolymerization and the like then mixing it with liquid of (A)+(B)+(C)which contains a copolymer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present invention, water is the most preferably as medium.However, for the purpose of heightening the solubility of a cationicmonomer for copolymerization or increasing the permeability to a basicmaterial, it is possible to use water jointly with organic solventeasily soluble in water at the same time. And also, it is possible touse organic solvent only, easily soluble in water. As such organicsolvents, isopropyl alcohol, methanol, ethanol, propanol, acetone,methyl ethyl ketone, dioxane, ethylene glycol, propylene glycol,glycerin, methyl carbitol, ethyl carbitol, butyl carbitol, methylcellosolve, ethyl cellosolve, acetic acid, acetic acid esters of theabove alcohol, acetic acid esters of the above carbitol, acetic acidesters of the above cellosolve and the like are available. In using suchorganic solvents together at the same time, from the viewpoint of safetyof aqueous liquid obtained, it is preferable that a ratio of organicsolvent in total medium is not more than 50% (by weight; the sameapplies hereinafter) and it is further preferable that the ratio is notmore than 20%. In using the above organic solvents, it is possible towithdraw the organic solvents by distillation and the like afterfinishing polymerization reaction.

Further, as a cationic monomer (component A) represented as the abovegeneral formula (1), methyl chloride salt of dimethylaminopropylmethacrylamide, acetate of dimethylaminopropyl methacrylamide, sulfateof dimethylaminopropyl methacrylamide, nitrate of dimethylaminopropylmethacrylamide, formate of dimethylaminopropyl methacrylamide, propionicacid salt of dimethylaminopropyl methacrylamide, ethyl chloride salt ofdimethylaminopropyl methacrylamide, methyl bromide salt ofdimethylaminopropyl methacrylamide, ethyl bromide salt ofdimethylaminopropyl methacrylamide, methyl iodide salt ofdimethylaminopropyl methacrylamide, methyl nitrate ofdimethylaminopropyl dimethylacrylamide, ethyl nitrate ofdimethylaminopropyl dimethylacrylamide, dimethyl sulfate ofdimethylaminopropyl methacrylamide, diethyl sulfate ofdimethylaminopropyl methacrylamide, hydrochloride of dimethylaminopropylmethacrylamide, hydrobromic acid salt of dimethylaminopropylmethacrylamide, hydroiodic acid salt of dimethylaminopropylmethacrylamide are available.

It is required that the above cationic monomer should be compounded at aratio of not less than 5% of total monomer (component A+componentB+component C). That is, when the ratio of cationic monomer is less than5%, the strength of the coat obtained and the adhesive strength withsurface finish and adhesive agent may not be adequate.

On the other hand, as an alkoxysilane monomer (B component) representedas the above general formula (2), 3-metharyloxy propyl trimethoxysilane,vinyl trimethoxysilane, vinyl triethoxysilane, vinyltrimethoxyethoxysilane, 3-methacryloxypropyl triethoxysilane, vinyltetramethylene trimethoxysilane, vinyl octamethylene trimethoxysilane,allyl trimethoxysilane, allyl triethoxysilane are available. It isrequired that the above alkoxysilane monomer should be compounded at aratio of not less than 0.5% of total monomer (A component+B component+Ccomponent). That is, when the ratio of alkoxysilane monomer is less than0.5%, the strength of the coat obtained and the adhesive strength andglued connection with surface finish and adhesive agent may not beadequate, as the same as the above cationic alkali crosslinkablemonomer.

Furthermore, as an ethylenic unsaturated monomer (C component), whichcan be used together with the above A component and B component,hydrophobic monomers such as vinyl acetate, alkyl acrylate esters, alkylmethacrylate esters, styrene, acrylonitrile, methacrylonitrile areavailable. Either of sole use of these or combination use of two or morewill do. And also, in case of preparing a polymer with the aboveethylenic unsaturated monomer, hydrophilic monomers such as acrylicacid, methacrylic acid, amides acrylate or methacrylate, methylolamides, alkoxymethyl amides, alkyl amino esters, vinylmonochloroacetate, methyl methacrylate, butyl acrylate, 2-ethyl hexylacrylate and the like may be used together with the above hydrophobicmonomer at the same time. Either of sole use or two or more will do inthis case, too. Of course, the above hydrophilic monomers should be usedwithin a limit so that the produced polymer may not be soluble inaqueous medium.

When the above ethylenic unsaturated monomers are copolymerized with theabove (A) component and (B) component, adhesive strength and gluedconnection with basic material surface, surface finish paint, adhesiveand the like will be further improved. In this case, it is required thatthe above ethylenic unsaturated monomer should be compounded at theratio of not less than 94.5% of the total monomer (A component+Bcomponent+C component).

It is also possible to accomplish the invention by mixing the mediumcontaining a copolymer made from (A)+(B)+the above ethylenic unsaturatedmonomer with a polymer (emulsion) made from the above ethylenicunsaturated monomer, the same effect can be obtained. In this case, itis preferable that a polymer (emulsion) (X) made from the ethylenicunsaturated monomer should be compounded to the above medium containinga copolymer made from A component+B component+C component at the ratioof X/Y=0/100 to 90/10.

Aqueous liquid for primers in the present invention can be made from theabove medium and each monomer, for example, in the following method.That is, first of all, polymerization initiator is added into water,organic solvent, or mixture of water and organic solvent as apolymerization medium, and then the above cationic monomer, alkoxysilanemonomer and ethylenic unsaturated monomer are dropped to polymerize atthe temperature of 60° to 90° C. over a period of 1 to 5 hours, asmaintaining the chemical system in acid condition. If necessary, chaintransfer agent such as lauryl mercaptane, 2-mercaptoethanol and the likeshould be added in advance to adjust molecular weight. And also, it ispossible to add a variety of addition agents, for example, film makingassistant, such as butyl cellosolve, butyl carbitol, and acetate,antifoaming agent, pigment, viscosity inhibitor and the like, should beadded as necessity requires. Thus the aqueous liquid for primers, whichis the object, can be obtained.

In addition, in case of emulsion polymerizing the ethylenic unsaturatedmonomer separately, publicly known prior method for emulsionpolymerization is available. And then emulsion obtained should be mixedwith the medium containing the above copolymer (a copolymer comprisingA+B+the ethylenic unsaturated monomer) so that aqueous liquid forprimers as an object can be materialized.

Further, it is required to selectively use medium which does not inhibitpolymerization in the above method. As the above polymerizationinitiator, azobis isobutyronitrile, benzoyl peroxide(2,2'-azobis-amino-dipropane hydrochloride, ammonium persulfate and thelike can be available. Furthermore, it is important to maintain theabove medium in acid condition because it prevents chemical system fromgelatinization. As acid for adjusting pH, organic acid such as formicacid, acetic acid, oxalic acid and the like, and inorganic acid such ashydrochloric acid, sulfuric acid, nitric acid and the like can beavailable.

Aqueous liquid for primers obtained in the above can be applied tosurfaces of inorganic basic materials such as concrete, mortar, slateplates, light weight calcium plates, ALC plates and the like as primer.This coating liquid can quickly penetrate the surface layer of basicmaterials as the medium penetrates, and in a drying process, functiongroup activated by alkali and water makes crosslinking formation so thata strong coat of three dimensional network structure superior inwaterproof and alkali resistance can be formed. As a results, strong anddurable reinforcement can be realized as strong as in the case thatsolvent primer liquid is used.

Still furthermore, aqueous liquid for primers in the present inventionis superior from viewpoint of safety and public nuisance preventionwithout volatilization of poisonous solvent because hydrophilic mediumis adopted. Even furthermore, since cation accounts for a portion ofconstitutional ingredients of aqueous liquid in the present invention,affinity and adhesion to paint for surface finish or adhesive agent,coated on the primer layer, are superior thanks to the characteristic ofcation, so that the surface finish layer can be attached strongly to thebasic materials.

EXAMPLE 1-9, COMPARATIVE EXAMPLE A-E

86 parts by weight (abbreviated as parts hereinafter) of isopropylalcohol was charged into a four-neck flask installed with dispersingblades, a thermometer and a reflux condenser and the 0.9 parts of azobisisobutyronitrile as polymerization initiator, 1.0 parts of laurylmercaptan, 1.0 parts of acetic acid as pH adjuster were added thereto.Monomer raw materials composed of ingredients shown in the followingtable 1 to 3 were charged into a dropping funnel and then dropped at therefluxing temperature for isopropyl alcohol over a period of 4 hourswith dispersing in order to polymerize and further 0.1 parts of azobisisobutyronitrile was added thereto for complete reaction for two hours.And then 240 parts of water was charged thereto to dissolve resinuniformly, and then isopropyl alcohol was withdrawn at 65° C. underreduced pressure. Each liquid containing a polymer thus obtained wasuniform solution wherein the concentration of the polymer was 30%,viscosity was 50 to 100 cps (BM type viscometer, 30° C.) and pH was 3.5to 4.0.

                                      TABLE 1                                     __________________________________________________________________________                                    Example                                                                       1  2  3 4 5                                   __________________________________________________________________________    Monomer                                                                             A component                                                                          Methyl chloride salt of dimethylamino-                                                           5  -- 20                                                                              --                                                                              75                                  composi-     propyl methacrylamide                                            tion         Acetate of dimethylaminopropyl meth-                                                             -- 5  --                                                                              20                                                                              --                                  (parts by    acrylamide                                                       weight)                                                                             B component                                                                          3-methacryloxypropyl trimethoxy silane                                                           0.5                                                                              0.5                                                                               3                                                                               3                                                                               5                                               vinyl trimethoxy silane                                                                          -- -- --                                                                              --                                                                              --                                        Unsaturated                                                                          methyl methacrylate                                                                              49.5                                                                             49.5                                                                             32                                                                              32                                                                              --                                        monomer                                                                              butyl acrylate     20 20 20                                                                              20                                                                              20                                               2-ethyl hexyl acrylate                                                                           20 20 20                                                                              20                                                                              --                                               styrene            5  5   5                                                                               5                                                                              --                                  __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________                                    Example                                                                       6 7 8 9                                       __________________________________________________________________________    Monomer                                                                             A component                                                                          Methyl chloride salt of dimethylamino-                                                           --                                                                              75                                                                              20                                                                              --                                      Composi-     propyl methacrylamide                                            tion         Acetate of dimethylaminopropyl meth-                                                             75                                                                              --                                                                              --                                                                              5                                       (parts by    acrylamide                                                       weight)                                                                             B component                                                                          3-methacryloxy propyl trimethoxy                                                                  5                                                                              --                                                                              --                                                                              --                                                   silane                                                                        vinyl trimethoxysilane                                                                           --                                                                               5                                                                               3                                                                              0.5                                           Unsaturated                                                                          methyl methacrylate                                                                              --                                                                              --                                                                              32                                                                              49.5                                          monomer                                                                              butyl acrylate     20                                                                              20                                                                              20                                                                              20                                                   2-ethyl hexyl acrylate                                                                           --                                                                              --                                                                              20                                                                              20                                                   styrene            --                                                                              --                                                                               5                                                                              5                                       __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________    Comparative Examples                                                                                           Example                                                                       A  B  C  D  E                                __________________________________________________________________________    Monomer  A component                                                                          Methyl chloride salt of dimethyl-                                                              5  -- 3  -- 2                                Composition     aminopropyl methacrylamide                                    (parts by weight)                                                                             Acetate of dimethylaminopropyl                                                                 -- 5  -- 3  --                                               methacrylamide                                                         B component                                                                          3-methacryloxy propyl trimethoxy                                                               0.3                                                                              0.3                                                                              0.5                                                                              0.5                                                                              --                                               silane                                                                        vinyl trimethoxysilane                                                                         -- -- -- -- 0.5                                       Unsaturated                                                                          methyl methacrylate                                                                            49.7                                                                             49.7                                                                             51.5                                                                             51.5                                                                             51.5                                      monomer                                                                              butyl acrylate   20 20 20 20 20                                               2-ethyl hexyl acrylate                                                                         20 20 20 20 20                                               styrene          5  5  5  5  5                                __________________________________________________________________________

All samples in these examples and comparative examples were applied totwo kinds of asbestos cement calcium silicate plates (one was pH of 9,the other was pH of 7, specific gravity was 0.7 for both) at the ratioof 15% concentration and 100 g/m² and then let them alone to dry at roomtemperature for 7 days. Later, the were divided into twenty five piecesof micro partition in 4 mm×4 mmm wherein gridiron pattern was made.After adhesive tape (Nichiban brand cellophane tape of 24 mm in width)was attached thereto and peeled off, the number of micro partitionremained on the part of basic materials was counted. Adhesive propertywith primer layer and paint for finish surface was valued thereby. Inaddition, all the samples were dipped into warm water of 60° C. for 7days after drying prior to dividing into partitions and then warm waterresisting adhesion was valued in the same method as above. As a resultof the above adhesive test, the samples with not less than 23 leftadhered were represented as , the samples with 20 to 22 as ◯, thesamples with 10 to 19 as -, the samples with not more than 9 as X. Theseresults are shown in the following Tables 4 to 7.

Furthermore, all samples of the above examples and comparative exampleswere applied to slate plates at the ratio of 15% concentration and 100g/m² and then left alone for drying at room temperature for 7 days.Later, waterproofing test was performed in accordance with JISA-6910.Samples wherein volume of water permeability one day after were not morethan 1 cc were represented as , not more than 3 cc as ◯, not more than 5cc as -, not less than X. These results are also shown in the followingTables 4 to 7.

                  TABLE 4                                                         ______________________________________                                                               Example                                                                       1   2     3     4                                      ______________________________________                                        Asbestos cement calcium                                                                      Adhesion in normal                                             silicate plates (basic                                                                       condition                                                      material surface layer                                                                       Adhesion in warm                                               pH = 9)        water                                                          Asbestos cement calcium                                                                      Adhesion in normal                                             silicate plates (basic                                                                       condition                                                      material surface layer                                                                       Adhesion in warm                                               pH = 7)        water                                                          Slate plates   Waterproof                                                     ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                                               Example                                                                       5   6     7     8                                      ______________________________________                                        Asbestos cement calcium                                                                      Adhesion in normal                                             silicate plates (basic                                                                       condition                                                      material surface layer                                                                       Adhesion in warm                                               pH = 9)        water                                                          Asbestos cement calcium                                                                      Adhesion in normal                                             silicate plates (basic                                                                       condition                                                      material surface layer                                                                       Adhesion in warm                                               pH = 7)        water                                                          Slate plates   Waterproof                                                     ______________________________________                                    

                                      TABLE 6                                     __________________________________________________________________________                                      Example                                                                            Comparative Example                                                      9    A    B C                               __________________________________________________________________________    Asbestos cement calcium silicate plates (basic                                                      Adhesion in normal                                                                                    ◯                   material surface layer pH = 9)                                                                      condition                                                                     Adhesion in warm water                                                                         ◯                                                                      ◯                                                                   ⊖                       Asbestos cement calcium silicate plates (basic                                                      Adhesion in normal                                                                                    ◯                   material surface layer pH = 7)                                                                      condition                                                                     Adhesion in warm water                                                                         ◯                                                                      ◯                                                                   X                               Slate plates          Waterproof       ◯                                                                      ⊖                                                                       ⊖                       __________________________________________________________________________

                  TABLE 7                                                         ______________________________________                                                               Comparative                                                                   Example                                                                        D   E                                                 ______________________________________                                        Asbestos cement calcium                                                                      Adhesion in normal                                                                           ◯                                                                       ◯                             silicate plates (basic                                                                       condition                                                      material surface layer                                                                       Adhesion in warm                                                                             ⊖                                                                           ⊖                                 pH = 9)        water                                                          Asbestos cement calcium                                                                      Adhesion in normal                                                                           ◯                                                                       ◯                             silicate plates (basic                                                                       condition                                                      material surface layer                                                                       Adhesion in warm                                                                             X     X                                         pH = 7)        water                                                          Slate plates   Waterproof     X     X                                         ______________________________________                                    

From the results of the above Tables 4 to 7, it is found out that everysamples of examples has superior properties compared with comparativeexamples.

EXAMPLES 10 TO 12, COMPARATIVE EXAMPLE F

An emulsion polymer (emulsion A) was produced in the followingcomposition, and then mixed with the samples gained in the above example2 in accordance with the composition of Table 8 shown later, so thataqueous liquid for primers was obtained.

    ______________________________________                                        <Composition of Emulsion A>                                                   Butyl acrylate           50      parts                                        Methyl methacrylate      48      parts                                        Dimethyl diallyl ammonium chloride                                                                     2       parts                                        Emulgen 935 (Product of Kao)                                                                           4       parts                                        Water                    156     parts                                        Ammonium persulfate      0.3     parts                                        <General Characteristic of Emulsion A>                                        Non-volatile residue     38.2%                                                Viscosity                200     cps                                          pH                       2.8                                                  Lowest temperature for making film                                                                     5°                                                                             C.                                           ______________________________________                                    

Next, as for aqueous liquid for primer obtained in the above method, thecharacteristics (adhesive test in normal conditions and warm water,waterproofing test) were valued in the same method of Example 1. Theresults were also shown in the following Table 8.

                                      TABLE 8                                     __________________________________________________________________________                                                Comparative                                                       Example     Example                                                           10  11  12  F                                 __________________________________________________________________________    Mixture of composition (parts by weight)                                                            Aqueous liquid of                                                                       75  50  25  --                                                      Example 2                                                                     Emulsion A                                                                              25  50  75  100                                                     Pondage   150 125 100 100                               Concentration (%)               18.8                                                                              19.6                                                                              20.5                                                                              19.0                              Asbestos cement calcium silicate plates (basic                                                      Adhesion in normal                                                                                  X                                 material surface layer pH = 9)                                                                      condition                                                                     Adhesion in warm                                                                                    X                                                       water                                                   Asbestos cement calcium silicate plates (basic                                                      Adhesion in normal                                                                                  X                                 material surface layer pH = 7)                                                                      condition                                                                     Adhesion in warm                                                                                    X                                                       water                                                   State plates          Waterproof                                                                                          X                                 __________________________________________________________________________

From the results of the above Table 8, it is found out that when anunsoluble polymer emulsion was separately produced, and then mixed withthe samples of the above examples, preferable liquid for primers canalso be obtained.

EFFECTS OF THE INVENTION

Aqueous liquid for primers in the present invention contains a copolymercomposed of two kinds of special monomers (A component and B component)and an ethylenic unsaturated monomer (C component) at a specific ratio,wherein a strong coat superior in waterproof and alkali resistanceproperty by crosslinking reaction can be formed irrespective of thedegree of alkali of basic materials. In addition, resin in highconcentration and low viscosity can be materialized withoutdeteriorating the speed of crosslinking reaction compared with priormethod, so that is has superior permeability to the basic materials,adequate reinforce ability to basic materials and waterproof under highconcentration condition. Therefore, in spite of aqueous property, itshows a superior reinforcing effect to basic materials, which is notless than that of prior solvent type primers, and furthermore, is safeand does not become a source for public nuisance. In addition, it showsaffinity to paints for surface finish, adhesives, or the like and hassuperior effects to strongly attach the finishing layer comprising theabove component on the surface of basic material.

What is claimed is:
 1. Aqueous liquid for primers, which contains acopolymer consisting essentially of the following components (A), (B)and (C) in aqueous medium where (A) is a cationic monomer represented bythe following general formula (1) ##STR5## wherein Y is organic orinorganic monovalent anion; m is an integer 0 to 3 and n is an integer 1to 3;(B) is an alkoxysilane monomer represented as the following generalformula (2) ##STR6## (C) is an ethylenic unsaturated monomer; andwherein a structural unit derived from the (A) component accounts fornot less than 5% of the copolymer, a structural unit derived from the(B) component accounts for not less than 0.5% by weight of the copolymerand a structural unit derived from the (C) component accounts for notmore than 94.5% by weight of the copolymer.
 2. Aqueous liquid forprimers which contains a dispersion of a copolymer formed according toclaim 1.